DALLAS (CBS News) — A white former police officer was sentenced to 15 years in prison Wednesday night, after being convicted of murdering an unarmed 15-year-old boy when he fired into a car packed with black teenagers leaving a house party in suburban Dallas. The verdict marked an extremely rare murder conviction for shootings involving on-duty police officers.

Roy Oliver, who faced up to life in prison, was sentenced one day after being convicted in the 2017 death of Jordan Edwards. His lawyers are expected to appeal.

Oliver was a police officer in Balch Springs when he and his partner responded to reports of underage drinking at the party. Oliver fired into a car carrying Edwards and his friends, later saying he feared the vehicle was moving toward and endangering his partner. Edwards, who was in the front passenger seat, was shot.

Police initially said the vehicle backed up toward officers “in an aggressive manner,” but later admitted that bodycam video showed the vehicle was moving forward as officers approached. Oliver’s partner told jurors he didn’t believe his life was ever in danger.

Investigators said no guns were found in the vehicle. Oliver was fired from the Balch Springs Police Department days after the shooting.

Around 7:15 p.m. Wednesday, the jury sent out a note asking the judge what do they do if they can’t reach a verdict, CBS Dallas / Fort Worth reports. The judge replied they have all the information they need to make a decision. If jury can’t come to a decision, it will be a hung jury and a new jury would have to be picked to come up with the punishment.

During the sentencing phase, people who say they know Oliver best – co-workers and friends – painted a picture of a man who is well-loved and respected in the community, CBS Dallas / Fort Worth reports.

Billie Gorwood, who once had Oliver as a tenant, begged the jury for leniency. “He wants to help and he wants to protect. And this tragedy has gone against everything, everything that Roy believes in.”

Edwards’ stepmother, Charmaine Edwards, took the stand after the verdict was read Tuesday. “It’s just trying to get through life without him now, and it’s hard because he had a promising future,” she said.

When the verdict was read Tuesday, gasps echoed around the courtroom. Edwards’s relatives sobbed and hugged prosecutors, waved their hands in the air and proclaimed “Thank you, Jesus!”

“I just want to say I’m happy, very happy,” Edwards father, Odell Edwards, said outside the courtroom. He said it had “been a long time” since he felt that way.

The jury, which featured two black members out of 12 jurors and two alternates, acquitted Oliver on two lesser charges of aggravated assault stemming from the shooting.

It’s extremely rare for police officers to be tried and convicted of murder for shootings that occurred while they are on duty. Only six non-federal police officers have been convicted of murder in such cases – and four of those convictions were overturned – since 2005, according to data compiled by criminologist and Bowling Green State University professor Phil Stinson.

Edwards’ father has also filed a civil lawsuit in connection to the shooting.